#!/bin/sh
# -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
# ex: ts=8 sw=4 sts=4 et filetype=sh
# SPDX-License-Identifier: LGPL-2.1-or-later
#
# This file is part of systemd.
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# systemd is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with systemd; If not, see <http://www.gnu.org/licenses/>.

skip_remaining=77

usage()
{
    echo "Usage:"
    echo "  kernel-install [OPTIONS...] add KERNEL-VERSION KERNEL-IMAGE [INITRD-FILE...]"
    echo "  kernel-install [OPTIONS...] remove KERNEL-VERSION"
    echo "  kernel-install [OPTIONS...] inspect"
    echo "Options:"
    echo "  -h, --help     Print this help and exit"
    echo "      --version  Print version string and exit"
    echo "  -v, --verbose  Increase verbosity"
}

dropindirs_sort()
{
    suffix="$1"
    shift

    for d; do
        for i in "$d/"*"$suffix"; do
            [ -e "$i" ] && echo "${i##*/}"
        done
    done | sort -Vu | while read -r f; do
        for d; do
            if [ -e "$d/$f" ]; then
                [ -x "$d/$f" ] && echo "$d/$f"
                continue 2
            fi
        done
    done
}

export LC_COLLATE=C

for i; do
    if [ "$i" = "--help" ] || [ "$i" = "-h" ]; then
        usage
        exit 0
    fi
done

for i; do
    if [ "$i" = "--version" ]; then
        echo "kernel-install {{PROJECT_VERSION}} ({{GIT_VERSION}})"
        exit 0
    fi
done

if [ "$KERNEL_INSTALL_BYPASS" = "1" ]; then
    echo "kernel-install: Skipping execution because KERNEL_INSTALL_BYPASS=1"
    exit 0
fi

export KERNEL_INSTALL_VERBOSE=0
if [ "$1" = "--verbose" ] || [ "$1" = "-v" ]; then
    shift
    export KERNEL_INSTALL_VERBOSE=1
fi

if [ "${0##*/}" = "installkernel" ]; then
    COMMAND=add
    # kernel's install.sh invokes us as
    #   /sbin/installkernel <version> <vmlinuz> <map> <installation-dir>
    # We ignore the last two arguments.
    set -- "$1"
else
    COMMAND="$1"
    [ $# -ge 1 ] && shift
fi

if [ "$COMMAND" = "inspect" ]; then
    KERNEL_VERSION=""
else
    if [ $# -lt 1 ]; then
        echo "Error: not enough arguments" >&2
        exit 1
    fi

    KERNEL_VERSION="$1"
    shift
fi

# These two settings are settable in install.conf
layout=
initrd_generator=

if [ -r "/etc/kernel/install.conf" ]; then
    install_conf="/etc/kernel/install.conf"
elif [ -r "/usr/lib/kernel/install.conf" ]; then
    install_conf="/usr/lib/kernel/install.conf"
else
    install_conf=
fi

if [ -n "$install_conf" ]; then
    [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "Reading $install_conf…"
    # shellcheck source=/dev/null
    . "$install_conf"
    # FIXME: This may override configuration in environment variables, e.g. $BOOT_ROOT.
fi

[ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && [ -n "$layout" ] && \
    echo "$install_conf configures layout=$layout"
[ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && [ -n "$initrd_generator" ] && \
    echo "$install_conf configures initrd_generator=$initrd_generator"

[ -n "$MACHINE_ID" ] && [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && \
    echo "machine-id $MACHINE_ID set via environment or install.conf"
[ -n "$BOOT_ROOT" ] && [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && \
    echo "BOOT_ROOT=$BOOT_ROOT set via environment or install.conf"

# If /etc/machine-id is initialized we'll use it, otherwise we'll use a freshly
# generated one. If the user configured an explicit machine ID to use in
# /etc/machine-info to use for our purpose, we'll use that instead (for
# compatibility).
# shellcheck source=/dev/null
if [ -z "$MACHINE_ID" ] && [ -r /etc/machine-info ] && . /etc/machine-info && MACHINE_ID="$KERNEL_INSTALL_MACHINE_ID"; then
    [ -n "$MACHINE_ID" ] && [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && \
        echo "machine-id $MACHINE_ID acquired from /etc/machine-info"
fi
if [ -z "$MACHINE_ID" ] && [ -r /etc/machine-id ] && read -r MACHINE_ID </etc/machine-id; then
    [ -n "$MACHINE_ID" ] && [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && \
        echo "machine-id $MACHINE_ID acquired from /etc/machine-id"
fi
if [ -z "$MACHINE_ID" ]; then
    MACHINE_ID="$(systemd-id128 new)" || exit 1
    [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "new machine-id $MACHINE_ID generated"
fi

# Now that we determined the machine ID to use, let's determine the "token" for
# the boot loader entry to generate. We use that for naming the directory below
# $BOOT where we want to place the kernel/initrd and related resources, as well
# for naming the .conf boot loader spec entry. Typically this is just the
# machine ID, but it can be anything else, too, if we are told so.
if [ -z "$ENTRY_TOKEN" ] && [ -r /etc/kernel/entry-token ] && read -r ENTRY_TOKEN </etc/kernel/entry-token; then
    [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && \
        echo "entry-token \"$ENTRY_TOKEN\" acquired from /etc/kernel/entry-token"
fi
if [ -z "$ENTRY_TOKEN" ]; then
    # If not configured explicitly, then use a few candidates: the machine ID,
    # the IMAGE_ID= and ID= fields from /etc/os-release and finally the fixed
    # string "Default"
    ENTRY_TOKEN_SEARCH="$MACHINE_ID"
    # shellcheck source=/dev/null
    [ -r /etc/os-release ] && . /etc/os-release
    [ -n "$IMAGE_ID" ] && ENTRY_TOKEN_SEARCH="$ENTRY_TOKEN_SEARCH $IMAGE_ID"
    [ -n "$ID" ] && ENTRY_TOKEN_SEARCH="$ENTRY_TOKEN_SEARCH $ID"
    ENTRY_TOKEN_SEARCH="$ENTRY_TOKEN_SEARCH Default"
else
    ENTRY_TOKEN_SEARCH="$ENTRY_TOKEN"
fi
[ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "Entry-token candidates: $ENTRY_TOKEN_SEARCH"

# NB: The $MACHINE_ID is guaranteed to be a valid machine ID, but
#     $ENTRY_TOKEN can be any string that fits into a VFAT filename, though
#     typically is just the machine ID.

if [ -n "$BOOT_ROOT" ]; then
    # If this was already configured, don't try to guess
    BOOT_ROOT_SEARCH="$BOOT_ROOT"
else
    BOOT_ROOT_SEARCH="/efi /boot /boot/efi"
fi

for pref in $BOOT_ROOT_SEARCH; do
    for suff in $ENTRY_TOKEN_SEARCH; do
        if [ -d "$pref/$suff" ]; then
            [ -z "$BOOT_ROOT" ] && BOOT_ROOT="$pref"
            [ -z "$ENTRY_TOKEN" ] && ENTRY_TOKEN="$suff"

            [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && \
                echo "$pref/$suff exists, using BOOT_ROOT=$BOOT_ROOT, ENTRY_TOKEN=$ENTRY_TOKEN"
            break 2
        else
            [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "$pref/$suff not found…"
        fi

        if [ -d "$pref/loader/entries" ]; then
            [ -z "$BOOT_ROOT" ] && BOOT_ROOT="$pref"
            [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && \
                echo "$pref/loader/entries exists, using BOOT_ROOT=$BOOT_ROOT"
            break 2
        else
            [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "$pref/loader/entries not found…"
        fi
    done
done

[ -z "$BOOT_ROOT" ] && for pref in "/efi" "/boot/efi"; do
    if mountpoint -q "$pref"; then
        BOOT_ROOT="$pref"
        [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && \
            echo "$pref is a mount point, using BOOT_ROOT=$BOOT_ROOT"
        break
    else
        [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "$pref is not a mount point…"
    fi
done

if [ -z "$BOOT_ROOT" ]; then
    BOOT_ROOT="/boot"
    [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && \
        echo "KERNEL_INSTALL_BOOT_ROOT autodection yielded no candidates, using \"$BOOT_ROOT\""
fi

if [ -z "$ENTRY_TOKEN" ]; then
    ENTRY_TOKEN="$MACHINE_ID"
    [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && \
        echo "No entry-token candidate matched, using \"$ENTRY_TOKEN\" from machine-id"
fi

if [ -z "$layout" ]; then
    # No layout configured by the administrator. Let's try to figure it out
    # automatically from metadata already contained in $BOOT_ROOT.
    if [ -e "$BOOT_ROOT/loader/entries.srel" ]; then
        read -r ENTRIES_SREL <"$BOOT_ROOT/loader/entries.srel"
        if [ "$ENTRIES_SREL" = "type1" ]; then
            # The loader/entries.srel file clearly indicates that the installed
            # boot loader implements the proper standard upstream boot loader
            # spec for Type #1 entries. Let's default to that, then.
            layout="bls"
        else
            # The loader/entries.srel file indicates some other spec is
            # implemented and owns the /loader/entries/ directory. Since we
            # have no idea what that means, let's stay away from it by default.
            layout="other"
        fi
        [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && \
            echo "$BOOT_ROOT/loader/entries.srel with '$ENTRIES_SREL' found, using layout=$layout"

    elif [ -d "$BOOT_ROOT/$ENTRY_TOKEN" ]; then
        # If the metadata in $BOOT_ROOT doesn't tell us anything, then check if
        # the entry token directory already exists. If so, let's assume it's
        # the standard boot loader spec, too.
        layout="bls"

        [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "$BOOT_ROOT/$ENTRY_TOKEN exists, using layout=$layout"
    else
        # There's no metadata in $BOOT_ROOT, and apparently no entry token
        # directory installed? Then we really don't know anything.
        layout="other"

        [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "Entry-token directory not found, using layout=$layout"
    fi
fi

ENTRY_DIR_ABS="$BOOT_ROOT/$ENTRY_TOKEN/$KERNEL_VERSION"
[ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "Using ENTRY_DIR_ABS=$ENTRY_DIR_ABS"

# Provide a directory where to store generated initrds
cleanup() {
    [ -n "$KERNEL_INSTALL_STAGING_AREA" ] && rm -rf "$KERNEL_INSTALL_STAGING_AREA"
}

trap cleanup EXIT

KERNEL_INSTALL_STAGING_AREA="$(mktemp -d -t kernel-install.staging.XXXXXXX)"

export KERNEL_INSTALL_MACHINE_ID="$MACHINE_ID"
export KERNEL_INSTALL_ENTRY_TOKEN="$ENTRY_TOKEN"
export KERNEL_INSTALL_BOOT_ROOT="$BOOT_ROOT"
export KERNEL_INSTALL_LAYOUT="$layout"
export KERNEL_INSTALL_INITRD_GENERATOR="$initrd_generator"
export KERNEL_INSTALL_STAGING_AREA

[ "$layout" = "bls" ]
MAKE_ENTRY_DIR_ABS=$?

ret=0

PLUGINS="$(
    dropindirs_sort ".install" \
        "/etc/kernel/install.d" \
        "/usr/lib/kernel/install.d"
)"
IFS="
"

[ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && printf '%s\n' "Plugin files:" "$PLUGINS"

case "$COMMAND" in
    add)
        if [ $# -lt 1 ]; then
            echo "Error: command 'add' requires a kernel image" >&2
            exit 1
        fi

        if ! [ -f "$1" ]; then
            echo "Error: kernel image argument $1 not a file" >&2
            exit 1
        fi

        if [ "$MAKE_ENTRY_DIR_ABS" -eq 0 ]; then
            # Compatibility with earlier versions that used the presence of $BOOT_ROOT/$ENTRY_TOKEN
            # to signal to 00-entry-directory to create $ENTRY_DIR_ABS
            # to serve as the indication to use or to not use the BLS
            if [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ]; then
                echo "+mkdir -v -p $ENTRY_DIR_ABS"
                mkdir -v -p "$ENTRY_DIR_ABS" || exit 1
            else
                mkdir -p "$ENTRY_DIR_ABS" || exit 1
            fi
        fi

        for f in $PLUGINS; do
            [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "+$f add $KERNEL_VERSION $ENTRY_DIR_ABS" "$@"
            "$f" add "$KERNEL_VERSION" "$ENTRY_DIR_ABS" "$@"

            err=$?
            [ $err -eq $skip_remaining ] && break
            [ $err -ne 0 ] && exit $err
        done
        ;;

    remove)
        for f in $PLUGINS; do
            [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "+$f remove $KERNEL_VERSION $ENTRY_DIR_ABS"
            "$f" remove "$KERNEL_VERSION" "$ENTRY_DIR_ABS"
            err=$?
            [ $err -eq $skip_remaining ] && break
            [ $err -ne 0 ] && exit $err
        done

        if [ "$MAKE_ENTRY_DIR_ABS" -eq 0 ]; then
            [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "Removing $ENTRY_DIR_ABS/"
            rm -rf "$ENTRY_DIR_ABS"
        fi
        ;;

    inspect)
        echo "KERNEL_INSTALL_MACHINE_ID: $KERNEL_INSTALL_MACHINE_ID"
        echo "KERNEL_INSTALL_ENTRY_TOKEN: $KERNEL_INSTALL_ENTRY_TOKEN"
        echo "KERNEL_INSTALL_BOOT_ROOT: $KERNEL_INSTALL_BOOT_ROOT"
        echo "KERNEL_INSTALL_LAYOUT: $KERNEL_INSTALL_LAYOUT"
        echo "KERNEL_INSTALL_INITRD_GENERATOR: $KERNEL_INSTALL_INITRD_GENERATOR"
        echo "ENTRY_DIR_ABS: $KERNEL_INSTALL_BOOT_ROOT/$ENTRY_TOKEN/\$KERNEL_VERSION"

        # Assert that ENTRY_DIR_ABS actually matches what we are printing here
        [ "${ENTRY_DIR_ABS%/*}" = "$KERNEL_INSTALL_BOOT_ROOT/$ENTRY_TOKEN" ] || { echo "Assertion didn't pass." >&2; exit 1; }
        ;;

    *)
        echo "Error: unknown command '$COMMAND'" >&2
        exit 1
        ;;
esac

exit "$ret"
